IEC NEC Code General Requirements 4 — Questions and Answers
Question 1: NEC 110.14(C) addresses temperature limitations of conductors at terminations. For conductors with 75°C rated insulation connected to a 60°C rated terminal, what temperature rating governs the ampacity?
- 75°C, since the conductor insulation allows it
- 60°C, since the lower-rated component governs (Correct answer)
- The average of 60°C and 75°C (67.5°C)
- Either rating may be used at the installer's discretion
Correct answer: 60°C, since the lower-rated component governs
NEC 110.14(C) requires that the ampacity be determined based on the lowest temperature rating of any connected component—in this case, the 60°C terminal.
Question 2: According to NEC 110.11, conductors and equipment must be protected against what environmental conditions if the use is not approved for that condition?
- High ambient temperatures above 40°C
- Deteriorating agents such as chemicals, moisture, and corrosive environments (Correct answer)
- Mechanical damage from tools and equipment
- UV radiation from sunlight exposure
Correct answer: Deteriorating agents such as chemicals, moisture, and corrosive environments
NEC 110.11 requires that conductors and equipment not suitable for deteriorating agents (chemicals, moisture, corrosives) be protected when exposed to such conditions.
Question 3: What does NEC 110.26(A)(1) Condition 2 specify for working space depth when there are exposed live parts on one side and grounded parts on the other?
- 3 feet
- 3.5 feet (Correct answer)
- 4 feet
- 6 feet
Correct answer: 3.5 feet
NEC 110.26(A)(1) Condition 2 requires 3.5 feet of working space depth when live parts are on one side and grounded parts are on the other.
Question 4: Under NEC 110.26(D), what must be provided to ensure illumination for all working spaces about electrical equipment?
- A minimum of 50 foot-candles of light at the equipment face
- Illumination for all working spaces about service equipment, switchboards, switchgear, panelboards, or motor control centers (Correct answer)
- Battery-backed emergency lighting at all electrical rooms
- Daylight-equivalent artificial lighting for all enclosures
Correct answer: Illumination for all working spaces about service equipment, switchboards, switchgear, panelboards, or motor control centers
NEC 110.26(D) requires that illumination be provided for all working spaces about service equipment, switchboards, switchgear, panelboards, or motor control centers.
Question 5: NEC 110.15 requires that single-phase, 3-wire systems have the high-leg conductor identified. What color must be used for this identification?
- Red
- Orange (Correct answer)
- Yellow
- Blue
Correct answer: Orange
NEC 110.15 requires the high leg of a 3-phase, 4-wire delta system to be identified with orange color.
Question 6: According to NEC 110.18, electrical equipment parts that are to be connected by wiring shall be capable of what?
- Accepting copper conductors only
- Accepting terminations of the conductors used (Correct answer)
- Being installed without tools
- Operating at the system's highest available voltage
Correct answer: Accepting terminations of the conductors used
NEC 110.18 requires that electrical equipment parts designed for field connection shall be capable of accepting the type and size of conductors used.
Question 7: What does NEC 110.26(A)(1) Condition 3 specify for working space depth when there are exposed live parts on both sides of the working space?
- 3.5 feet
- 4 feet
- 5 feet (Correct answer)
- 6 feet
Correct answer: 5 feet
NEC 110.26(A)(1) Condition 3 requires 4 feet of working space depth when live parts are exposed on both sides of the working space.
IEC NEC Code General Requirements 4
NEC 110.14(C) addresses temperature limitations of conductors at terminations.
For conductors with 75°C rated insulation connected to a 60°C rated terminal, what temperature rating governs the ampacity?